1. Field of the Invention
This invention relates to a process for producing from citrus peel or citrus albedo a dried clouding agent which does not impart any off-flavors when used in a citrus-type beverage.
2. Description of the Prior Art
All citrus juices, when freshly expressed, have a characteristic opacity of cloudiness. It is obviously desirable to maintain this opacity in processing citrus juices, and to emulate it in formulated citrus beverages. In the natural juices, "cloud" is provided by minute suspended or colloidal particles of citrus tissue and cell contents.
In formulated beverages, cloudiness is achieved by adding a suitable natural or chemical substance, such a titanium dioxide or brominated vegetable oil. Usually these substances are alien to citrus beverages. In keeping with the current consumer emphasis on natural ingredients, several efforts have been directed toward developing a clouding agent from citrus peel or citrus albedo.
U.S. Pat. No. 3,404,990, granted to Villadsen (1968) discloses a procedure whereby citrus peels are comminuted, heated and then enzyme treated to facilitate the extraction of clouding material. The entire mixture is briefly centrifuged to remove the pulp and the supernatant liquid is pasteurized. Excess water is then evaporated. The final clouding agent product is a liquid concentrate.
French Pat. No. 2,331,292 to Gouin (1975) describes a procedure which is basically similar, but the citrus albedo is sieved, milled and homogenized in such a way as to minimize the amount of pulp discarded, and no enzyme is added. The final clouding agent is a liquid concentrate which has the consistency of fresh cream.
Matthews, Herrera and Crandall of the University of Florida have recently developed a procedure wherein a clouding agent is obtained from the water which has been used to leach citrus peel during pectin or dietary fiber production. The final clouding agent is a liquid concentrate differing from the previous examples in that it is free of pectin and contains soluble carbohydrates as the major component.
Further examination of the literature leads to the conclusion that all prior procedures ultimately produce a liquid concentrate which consists of cloud particles and varying amounts of soluble carbohydrates, and (with the exception of the Matthews procedure) pectinaceous material. Bradock and Kesterson, from the University of Florida, have evaluated typical prior art clouding agents in their article "Use of Enzymes in Citrus Processing," Food Technology, Nov. 1979. They report the following problems:
1. The cloud may be quite bitter; this problem varies with the source of peel. PA1 2. The cloud concentrate has a tendency to brown or darken upon storage; this affects the color of the final beverage product. PA1 3. Clouding ability of the concentrate varies with each batch of peel, which would make standardization of the cloud level in the final beverage extremely difficult.
Villadsen discloses a preliminary boiling step to remove bitter tasting principles consisting of boiling the citrus peel in an equal volume of water for 30 minutes. The water is discarded, allegedly "removing the bitter-tasting principles or part thereof." In agreement with Bradock and Kesterson, experiments conducted by the inventors also demonstrated that the procedure disclosed in the Villadsen patent did not completely remove off-flavors, and that degree of flavor removal remained dependent on the variety and condition of the citrus peel or albedo starting material. In one particular experiment conducted by the present inventors, frozen orange albedo from a mixed batch of Hamlin and Pineapple varieties was utilized as the starting material. After thawing the albedo, the Villadsen extraction procedure was followed-however, the quantity of water was tripled and the extraction was performed twice. Then, in accordance with the teaching of the patent, the drained albedo was comminuted, treated with a pectinaceous enzyme, and freed of coarse material. The resulting cloudy suspension which is the product of the Villadsen process was evaluated in an orange flavored dried beverage mix; the quantity added was the amount required to provide the customary opacity. Benchtop tasters reported strong terpene-like flavors which made the final beverage unacceptable.
By contrast, a portion of the cloudy suspension described above was centrifuged to separate the clouding agent from the supernatant liquid, as taught in the present invention. A portion of this isolated clouding agent was washed with isopropyl alcohol, then water. A second portion was boiled with water, then washed with water. Both samples of isolated clouding agent were evaluated in an orange flavored dried beverage mix. Both were completely flavorless in the beverage.
In addition, it was found that the type of cloud concentrate produced according to prior art procedures is poorly suited for use in a dry formulated beverage because, in a dried state the components are quite unstable and very prone to off-flavor development.
Another disadvantage of these clouding concentrates is the set ratio of clouding capacity to pectin content. In order to obtain a desired opacity, it may be unavoidable to add much more pectin than is optimal for overall beverage quality.
The process of Matthews et al produces a final liquid concentrate which differs from those discussed above since pectin is not a component. However, it is combination of cloud particles and carbohydrates which vary in ratio with batches of peel, so a similar problem in uniformity of end product exists. The problem of inflexibility also exists. To achieve a desired opacity, a set amount of carbohydrates must be added. This restricts the formulator's choice of carbohydrate sources, limiting his ability to optimize flavor or minimize caloric value. Also, browning or darkening on storage has been reported as a problem which must be controlled by freezing or treatment with sulfur dioxide. Finally, the Matthews process was designed to utilize the waste from two relatively small industries. If large quantities of albedo cloud are required, this source is insufficient.